1. Field of the Invention
In one aspect, this invention relates to engine mounting devices. In a further aspect, this invention relates to vibration isolating bushings.
2. Prior art
The advent of four cylinder engines in vehicles has created a new set of problems for automotive engineers. Four cylinder engines inherently have a second order vibration greater than the six and eight cylinder engines presently in use. Such vibrations when transmitted to the automotive chassis on which the engine is mounted are disconcerting to the driver and contribute to general driver fatigue and irritability.
Prior art engine mounts generally comrpise a tubular housing surrounding a shaped rubber bushing featuring two voids. The bushing has a center aperture. The engine mount has the housing generally attached to the vehicle and the engine is mounted to the vehicle by means of a connector through the aperture. The void in the rubber bushing controls some of the vibrations in one direction, but in general allows the passage of vibration. Such engine mounts do not properly isolate the vibration of a four cylinder engine.
As an alternative, certain engines have installed counter balanced rotating shafts as part of the engine. Such systems work, but require the use of precision parts, increase the complexity of the engine, add substantial weight and increase cost.